Apparatus for forming variable height surgical fasteners

ABSTRACT

A surgical device for applying a plurality of surgical staples is provided. The device includes a staple fastening assembly attached to a surgical instrument. The staple fastening assembly includes a pair of cooperating jaws, a jaw operating mechanism, and a gap sensor. A staple magazine having a plurality of staples and an anvil member having a plurality of staple pockets are attached to the jaws. The staple magazine includes a staple crimping cam and a staple dimpling cam that are operatively coupled to the surgical instrument. The jaw operating mechanism is operatively connected to a drive assembly in the surgical instrument for moving the jaws for automatically setting a tissue gap between the cooperating jaws. The gap sensor cooperates with the jaw operating mechanism for controlling staple formation.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/343,743, filed on Jan. 5, 2012, which is a continuation of U.S.patent application Ser. No. 12/529,576, filed on Sep. 2, 2009, now U.S.Pat. No. 8,205,780, which is a National Stage Application ofPCT/US2008/057599, filed on Mar. 20, 2008 under 35 USC §371 (a), whichclaims priority to, and the benefit of, U.S. Provisional PatentApplication Ser. No. 60/919,381, filed on Mar. 22, 2007 the entirecontents of which are hereby incorporated by reference.

BACKGROUND

Technical Field

The present disclosure relates to surgical fastener apparatus. Moreparticularly, the present disclosure relates to apparatus for formingvariable height surgical fasteners to body tissue in surgicalprocedures.

Background of Related Art

Surgical devices wherein tissue is first grasped or clamped betweenopposing jaw structure and then joined by means of surgical fastenersare well known in the art. In some instruments, a knife is provided tocut the tissue which has been joined by the fasteners. The fasteners aretypically in the form of surgical staples.

Instruments for this purpose may include two elongated members which arerespectively used to capture or clamp tissue. Typically, one of themembers carries a cartridge which houses a plurality of staples arrangedin at least two lateral rows while the other member includes an anvilwhich defines a surface for forming the staple legs as the fasteners aredriven from the cartridge. Generally, the stapling operation is effectedby a pusher which travels longitudinally through the cartridge carryingmember, with the pusher acting upon the staples for sequentiallyejecting them from the cartridge. A knife may travel with the pusherbetween the staple rows to longitudinally cut and/or open the stapledtissue between the rows of staples.

A later stapler disclosed in U.S. Pat. No. 3,499,591 applies a doublerow of staples on each side of the incision. This is accomplished byproviding a cartridge assembly in which a cam member moves through anelongate guide path between two sets of staggered staple carryinggrooves. Staple drive members are located within the grooves and arepositioned in such a manner so as to be contacted by the longitudinallymoving cam to effect ejection of the staples. Other examples of staplersare disclosed in U.S. Pat. Nos. 4,429,695; 5,065,929; and 5,156,614.

SUMMARY

The present disclosure is directed towards a staple fastening assemblyfor use with a surgical instrument to apply surgical staples. The staplefastening assembly includes cooperative first and second jaws, a jawoperating mechanism, and a staple driving assembly. One jaw is generallyelongate and includes a staple magazine. The staple magazine may befixedly attached or releasably attached to the jaw and includes aplurality of staples arranged in at least one row. A first tissuecontacting surface is defined on one face of the staple magazine andincludes a plurality of retention slots corresponding to the number ofstaples included in the staple magazine. It is contemplated thatmultiple rows of staples may be provided and arranged in columns. Theretention slots may be longitudinally aligned or offset from oneanother. Each retention slot is configured and adapted for releasablyreceiving its respective staple. Each staple includes first and secondsubstantially parallel legs connected by a backspan formingsubstantially right angles to each of the legs.

The second jaw is generally elongate and movable throughout a pluralityof positions between an open position and a closed position. An anvilmember is disposed on the second jaw and includes a second tissuecontacting surface. The second tissue contacting surface includes aplurality of staple pockets wherein the number and arrangement of staplepockets corresponds to the number and arrangement of retention slots inthe staple magazine. The second tissue contacting surface is orientedsuch that it is in juxtaposition with the first tissue contactingsurface and defines a tissue gap therebetween.

Each staple pocket includes a pair of staple forming grooves forcapturing the legs of each staple. The staple forming grooves aresubstantially symmetrical about an intermediate point and have opposinginclined surfaces. A substantially lemniscate channeling surface isformed about a perimeter of each staple pocket. Each staple forminggroove urges one leg of each staple towards the other leg whilemaintaining lateral separation of the legs during and after stapleformation.

The jaw operating mechanism is disposed in a housing that is attached toa proximal portion of the staple fastening assembly. The jaw operatingmechanism includes a cam rotatably mounted to the housing, a cable, anda spring that are cooperatively coupled to one another. An approximatingmechanism in the surgical instrument is operatively coupled to the jawoperating mechanism to cause proximal motion of the spring. Proximalmovement of the spring is coupled to the cam via the cable. In oneembodiment, the cam has an eccentric outer surface for maintainingcontact between at least a portion of the outer surface of the cam andan outer surface of the second jaw. The cam may include an anti-reverseassembly (i.e. self-locking) to permit counter-clockwise rotation of thecam while inhibiting clockwise rotation of the cam. Configured thusly,counter-clockwise rotation of the eccentric cam continuously urges thesecond jaw towards the first jaw during proximal movement of the spring.The dimensions of the cam and the cable, as well as the dimensions andmaterial selected for the spring, contribute towards the tissuecapturing characteristics of the jaw operating mechanism. It isdesirable for the jaws to capture and hold tissue in position whileminimizing trauma to the tissue. Advantageously, the combination of thecam, the cable, and the spring allows for automatic adjustment of thetissue gap to accommodate different thicknesses of tissue duringstapling operations.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the presently disclosed surgical instrument are describedherein with reference to the drawings, wherein:

FIG. 1 is a side cross-sectional view of a staple fastening assembly inaccordance with an embodiment of the present disclosure in an openposition;

FIG. 2 is a side cross-sectional view of the staple fastening assemblyof FIG. 1 in an intermediate position;

FIG. 3 is a side cross-sectional view of the staple fastening assemblyof FIG. 1 in a closed position;

FIG. 4 is a top plan view of a staple magazine of the staple fasteningassembly of FIG. 1;

FIG. 5 is an exploded perspective view of a staple driving assemblyshowing the relationship among the several components;

FIG. 6 is a bottom plan view of an anvil member;

FIG. 6A is a top plan view of a staple pocket;

FIG. 7A is a side view of an unformed staple;

FIG. 7B is a side view of the staple of FIG. 7A formed to a firstconfiguration in accordance with the present disclosure;

FIG. 7C is a side view of the staple of FIG. 7A formed to a secondconfiguration in accordance with the present disclosure;

FIG. 7D is a side view of the staple of FIG. 7A formed to a thirdconfiguration in accordance with the present disclosure;

FIG. 7E is a side view of the staple of FIG. 7A formed to a fourthconfiguration in accordance with the present disclosure;

FIG. 7F is a plan view of the staple of FIG. 7B showing an overlapbetween first and second legs of the staple;

FIG. 8A is an enlarged side view of a staple pocket, an unformed staple,a staple sled, and a rod sled;

FIG. 8B is an enlarged side view of the components of FIG. 8A showingthe staple formed into a first configuration; and

FIG. 8C is an enlarged side view of the components of FIG. 8B showing abackspan of the staple being dimpled by the dimpling rod.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the presently disclosed surgical instrument will now bedescribed in detail with reference to the drawings, in which likereference numerals designate identical or corresponding elements in eachof the several views. As used herein, the term “distal” refers to thatportion of the instrument, or component thereof which is further fromthe user while the term “proximal” refers to that portion of theinstrument or component thereof which is closer to the user.

An example of a surgical stapling apparatus is disclosed in U.S. Pat.No. 5,480,089 to Blewett, currently owned by and assigned to UnitedStates Surgical, a division of Tyco Healthcare, the contents of whichare hereby incorporated by reference in their entirety. Referring toFIG. 1, a staple fastening assembly, shown generally as 100, includes afixed first jaw 104, a moveable second jaw 140, and a jaw operatingmechanism 160. In one embodiment, staple fastening assembly 100 isadapted for use in connection with endoscopic or laparoscopic staplinginstruments as are known in the art.

First jaw 104 includes a staple magazine 120 having a first tissuecontacting surface 122. A plurality of retention slots 124 is includedin staple magazine 120 where they are arranged in rows 126 on firsttissue contacting surface 122 (see FIG. 4). Each row 126 generallyextends along a longitudinal axis of first jaw 104. First tissuecontacting surface 122 is generally elongate. Each retention slot 124 isconfigured for receiving a staple 110 and a staple ejector assembly. Thestaple ejector assembly includes a staple ejector 132, a dimpling rod138 (see FIG. 5), a staple sled 134, and a rod sled 136. It iscontemplated that staple magazine 120 may be removably attached to firstjaw 104. In a configuration where staple magazine 120 is a removablestructure, once its complement of staples 110 have been expended, it maybe removed and a new staple magazine 120 is attached to first jaw 104.Each staple magazine 120 includes a full complement of staples 110 andat least one staple driving assembly 130 (shown in FIG. 5 and discussedin detail below).

Staple magazine 120 includes a plurality of longitudinal channels 128(see FIGS. 3 and 4) that are adapted for slidably receiving staple sled134 and rod sled 136. The number of channels 128 corresponds to thenumber of rows 126 of staples 110 included in staple magazine 120. Inone embodiment, staple magazine 120 include at least two rows 126 ofstaples 110, although the procedure being performed, characteristics ofthe tissue to be fastened, and other considerations are factors indetermining the number of rows 126, as well as the number of staples110, included in each staple magazine 120. Each row 126 in the pluralityof rows has an identical quantity of staples 110.

Referring now to FIGS. 5 and 8A-8C, in conjunction with FIGS. 1-3,staple driving assembly 130 is shown and it includes a staple ejector132, staple sled 134, rod sled 136, and a dimpling rod 138. Each staplesled 134 is operatively coupled to a drive mechanism (not shown) of thesurgical stapling instrument using structures that are known in the art.An example of such an instrument that includes a drive mechanism and anactuation mechanism is disclosed in U.S. Pat. No. 6,669,073 to Millimanet al., currently owned by and assigned to United States Surgical, adivision of Tyco Healthcare, the contents of which are herebyincorporated by reference in their entirety. In embodiments that includea plurality of rows 126, staple sleds 134 are operatively coupled to thedrive mechanism such that their longitudinal travel is synchronized forejecting a column 127 of staples 110 (see FIG. 4) substantiallysimultaneously during an actuation sequence. Operation of the drivemechanism results in proximal and distal movement of the respective camsin response to actuation of the actuation mechanism.

Staple sled 134 is a generally elongate structure having a pair ofinclined surfaces 135 a, 135 b oriented towards the distal end of staplemagazine 120. Inclined surfaces 135 a, 135 b are laterally spaced apartto define a passage 135 c therebetween. Passage 135 c is substantiallyflat and dimensioned for slidably receiving rod sled 136. Rod sled 136is a generally inclined structure having a substantially similar inclineto that of staple sled 134. Further still, staple ejector 132 includes apair of legs 132 a, 132 b that are laterally spaced apart and angled attheir distal ends for readily engaging inclined surfaces 135 a, 135 b. Athroughhole 132 c is centrally disposed in body 132 d of staple ejector132 and is dimensioned for slidably receiving dimpling rod 138.

Upon actuation of the actuation mechanism, staple sled 134 is driventhrough staple magazine 120 in a generally distal direction by the drivemechanism. As it translates through staple magazine 120, staple sled 134sequentially engages each staple ejector 132. Staple sled 134 and stapleejector 132 have engaging surfaces with complementary angles such thatdistal horizontal motion of staple sled 134 results in vertical motionof staple ejector 132 which, in turn, drives staple 110 in a generallyvertical direction towards anvil member 142. During distal movement ofstaple sled 134, rod sled 136 remains stationary in a proximal region ofthe magazine. In instances where a staple height of less than about 2.5mm is desirable, as determined by tissue gap 102, the actuationmechanism actuates the drive mechanism and drives rod sled 136 distallyas will be discussed in detail hereinafter.

With reference to FIGS. 2 and 3, a gap sensor 106 is disposed in aproximal portion of staple fastening assembly 100. Gap sensor 106 is agenerally elongate structure having a throughhole 109 disposed near oneend. Further still, gap sensor 106 is fixedly attached to second jaw 140and slidably received in an opening 105. A dimple window 103 is disposednear a proximal portion of first jaw 104 and is configured for slidablyreceiving a dimpling rod driver 107. Dimpling rod driver 107 isoperatively coupled to the actuation mechanism and engages stapledimpling cam 136 when dimple window 103 is aligned with dimpling roddriver 107. Gap sensor 106 is configured and dimensioned such thatdimpling window 103 is aligned with dimpling rod driver 107 only whentissue gap 102 indicates that a staple height of less than about 2.5 mmis desired.

In an embodiment having a staple height of less than about 2.5 mm,staple sled 134 leads rod sled 136 (FIG. 5) during their travel throughstaple magazine 120. As staple sled 134 translates distally throughstaple magazine 120, rod sled 136 follows it after a predetermined timedelay. Rod sled 136 is guided along its path by passage 135 c of staplesled 134. Therefore, staple sled 134 ejects staple 110 and drives itagainst anvil member 142 to form a staple having a height of about 2.5mm as discussed above. Once staple 110 has been driven into staplepocket 150, and before staple sled 134 passes staple ejector 132 (i.e.the delay between the sleds), sled 136 engages dimpling rod 138. As rodsled 136 translates distally with staple sled 134, it contacts dimplingrod 138 causing vertical motion thereof to engage backspan 116. Rod sled136 drives dimpling rod 138 such that it forms a depression in thecenter of backspan 116 and further increasing the holding strength ofthe formed staple 110.

As shown in FIG. 4, staple magazine 120 may have a plurality of rows 126where retention slots 124 in each row 126 may be longitudinally offsetfrom retention slots 124 in an adjacent row 126. Since retention slots124 are longitudinally offset, staple crimping cams 134 are operativelyarranged and synchronized to eject the first staple 110 from each row126 and advancing sequentially towards a distal end of staple magazine120 and sequentially ejecting staples 110 from each row 126.

As shown in FIGS. 1-3, second jaw 140 is spaced apart from first jaw 104defining a tissue gap 102 therebetween. Second jaw 140 is moveablethrough a plurality of positions between an open position and a closedposition. In one embodiment, first jaw 104 and second jaw 140 aresubstantially parallel to one another throughout the plurality ofpositions. During operation, discussed in detail below, of staplefastening assembly 100, second jaw 140 is moved towards first jaw 104 byjaw operating mechanism 160 that maintains a substantially parallelrelationship between jaws 104 and 140.

Referring to FIG. 1, jaw operating mechanism 160 is disposed in ahousing 170 and includes a cam 162, a cable 164, and a spring 166. Cam162, cable 164, and spring 166 are operatively connected to one another.A proximal portion of second jaw 140 is disposed within housing 170 andsecured thereto. In particular, spring 166 is operatively coupled to anapproximating mechanism (not shown) of the stapling instrument bystructures as are known in the art. The approximating mechanism causesspring 166 to move proximally. Since cable 164 is operatively connectedto spring 166, this proximal movement of spring 166 results in proximalmovement of cable 164 and counter-clockwise rotation of cam 162.

At least a portion of cam 162 contacts an outer surface 146 of secondjaw 140 and it is self-locking in the counter-clockwise direction ofrotation. Cam 162 has a centrally disposed orifice 163 for rotatablyattaching it to housing 170. Although orifice 163 is substantiallycircular, cam 162 has a generally eccentric shape, particularly along anoutside surface, such that counter-clockwise rotation of cam 162 causesat least a portion of cam 162 to maintain contact with outer surface 146thereby urging second jaw 140 towards first jaw 104 duringcounter-clockwise rotation. After cam 162 has rotated a desired amount,it locks in position such that no clockwise rotation is possible (i.e.self-locking), but additional counter-clockwise rotation is possible. Arelease mechanism, as is known in the art, operatively couples jawoperating mechanism 160 to the surgical stapling instrument. After acomplete actuation sequence, the release mechanism is actuated to unlockcam 162 and permit clockwise rotation of cam 162. Thusly, second jaw 140is urged away from first jaw 104 by a biasing mechanism as is known inthe art to separate the jaws and allow removal of the surgical staplinginstrument.

In one embodiment, cam 162, cable 164, and spring 166 are selected suchthat tissue T is captured and maintained between jaws 104, 140 using aminimum amount of applied pressure. The advantageous combination of cam162, cable 164, and spring 166 captures different thicknesses of tissueT (i.e. each tissue thickness corresponds to a particular tissue gap102) while minimizing trauma to tissue T as jaws 104, 140 capture tissueT therebetween.

Referring now to FIG. 6, an anvil member 142 is illustrated. Anvilmember 142 is generally elongate and includes a plurality of staplepockets 150 (see FIG. 6A) disposed on an second tissue contactingsurface 144 where the number and arrangement of staple pockets 150correspond to the number and arrangement of retention slots 124 in firsttissue contacting surface 122. An example of a staple pocket isdisclosed in U.S. Pat. No. 5,480,089 to Blewett. With reference now toFIG. 6A, each staple pocket 150 has a first staple leg forming groove152 and a second staple leg forming groove 154 for forming respectivelegs 112, 114 of staple 110 (see FIG. 7A). Each staple forming groove152, 154 is dimensioned to accommodate legs 112, 114 respectively.

Staple leg forming grooves 152 and 154 are symmetrical about anintermediate point 156. A substantially lemniscate (figure-eight shapedcurve) channeling surface 158 is also formed in second tissue contactingsurface 144 around a perimeter of staple pocket 150. Each channelingsurface 158 forms an angle θ, with respect to a plane defined by secondtissue contacting surface 144, wherein 0°<θ<90°. Each staple forminggroove 152, 154 has a different slope than that of adjacent channelingsurface 158. More particularly, each staple forming groove 152, 154 hasa sloped end 152 a, 154 a to direct a corresponding staple leg 112, 114towards a backspan 116 of staple 110. Sloped ends 152 a, 154 a arelongitudinally opposed to one another.

During an actuation sequence, staple 110 is ejected from retention slot124 and directed towards anvil member 142 thereby driving legs 112 and114 through tissue T to enter staple forming grooves 152, 154respectively. As staple 110 contacts staple pocket 150, staple forminggrooves 152, 154 direct legs 112, 114 towards each other whilemaintaining lateral separation of legs 112, 114 so that they overlap oneanother as shown in FIG. 7F. In particular, with reference to FIGS.7B-7D, during formation of staple 110, staple forming groove 152, incooperation with channeling surface 158, directs leg 112 towardsbackspan 116 alongside and substantially parallel to an unformed portionof leg 114. Similarly, staple forming groove 154, in cooperation withchanneling surface 158, directs leg 114 towards backspan 116 alongsideand substantially parallel to an unformed portion of leg 112. The amountof parallel overlap between leg 112 and the unformed portion of leg 114is a function of tissue gap 102. Similarly, the amount of paralleloverlap between leg 114 and the unformed portion of leg 112 is also afunction of tissue gap 102 that is controlled by the thickness of tissueT and operation of jaw operating mechanism 160.

Thusly, a larger tissue gap 102 results in a larger staple 110 height(e.g. about 4.8 mm as shown in FIG. 7B) while a smaller tissue gap 102yields a smaller staple 110 height (e.g. about 2.5 mm as shown in FIG.7D). In one embodiment, the actuation mechanism, in cooperation withstaple magazine 120 and anvil member 142, forms staples 110 having aheight of between about 4.8 mm (i.e. the open position of second jaw140) and about 2.5 mm (i.e. the closed position of second jaw 140) asdetermined by the thickness of tissue T and tissue gap 102. It is to beunderstood that staples 110 may be formed having any height that is inthe range of about 4.8 mm and about 2.5 mm as determined by thethickness of tissue T (an example is illustrated in FIG. 7C). Ininstances where tissue T thickness indicates a need for a smaller staple110 height (i.e. less than about 2.5 mm or the dimpling position as seenin FIG. 7E), the actuation mechanism of the stapling instrument operatesa second drive member that is operatively coupled to rod sled 136, asdiscussed hereinabove.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications ofpreferred embodiments. For example, the staple forming structuredisclosed herein can be adapted and configured for use in EEA, TA, andendoscopic staplers with similar effect. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

What is claimed is:
 1. A surgical apparatus comprising: a first jawincluding a plurality of retention slots; a second jaw including aplurality of grooves; a plurality of fasteners disposed in the pluralityof retention slots, each fastener including first and second legs,wherein each groove is configured to direct the legs of the fastenertowards each other resulting in a formed portion and an unformed portionin each leg, and wherein the formed portion of the first leg at leastpartially overlaps the unformed portion of the second leg; a firstdriving mechanism configured to urge the fastener towards the groove andincluding a first sled and an ejector, and wherein distal longitudinalmovement of the first sled through the first jaw causes movement of theejector towards the second jaw and urges the fastener towards thegroove; and a second driving mechanism including a second sled and amovable member, wherein distal longitudinal movement of the second sledthrough the first jaw causes movement of the movable member towards thesecond jaw, the moveable member of the second driving mechanism operableto deform a backspan of the fastener when a distance between the firstand second jaws is less than a predetermined value.
 2. The surgicalapparatus of claim 1, wherein each groove is configured to direct thefirst leg and the second leg of the fastener towards each other whilemaintaining lateral separation of the legs.
 3. The surgical apparatus ofclaim 1, wherein the formed portion of the first leg includes a sectionsubstantially parallel to the unformed portion of the second leg.
 4. Thesurgical apparatus of claim 1, wherein the formed portion of the secondleg at least partially overlaps the unformed portion of the first leg.5. The surgical apparatus of claim 4, wherein the formed portion of thesecond leg includes a section substantially parallel to the unformedportion of the first leg.